Recently, new alternative materials are participated by the production of composites which includes polymer fibers. The fibers in the form of "Technical Textiles" show variety and provide spreading the modern structure systems in "Textile Architecture". The fibers used in textile architectures are mainly polyester, polypropylene and polyamide fibers. Especially the fibers in the form of microfibers come forward because of the endurance against the climatic conditions. Microfiber textile surfaces has the air and water vapour permeability which is demanded for exterior coating, can also be used as exterior surface material when durability conditions were provided. In this research, the tensile strength of polyester microfiber material, used in textile industry, was researched under external conditions. Among these external conditions, especially UV radiation was an effective factor on the material surface. Due to this factor, different concentrations of UV absorbers were applied on microfiber. Undyed microfiber textile material was treated with 0%, 1%, 2%, 3% and 4% UV absorber concentrations. UV radiation of daylight was limited in 300-400 nm and material was exposed to accelerated aging experiment for 320 hours, which was equivalent to blue wool 7-18 degree reference. The experimental results showed that UV absorber has a positive effect on aged material; however, concentration percentage differences do not provide any annex to endurance of material.